Forehand forearm supination question

[BrianGordon]

I guess I don't see how the the supination/pronation action relates to the grip being used or to the wrist position except possibly as a matter of degree of vertical velocity production - this action will cause upward motion of the racquet face with any combination in realistic near contact configurations.

Certainly hitting up through contact creates topspin - in the final analysis it boils down to what anatomical rotations best accomplish this task. The options are wrist radial deviation, forearm pronation (combined with upper arm internal rotation with straighter arm configurations), elbow flexion, shoulder flexion and/or abduction, or lifting of the entire upper body through action of the legs and/or waist.

From a mechanical perspective, some seem much more attractive than others based on geometric considerations and the associated joint rotation speed potential and range of available motion. Just a thought (or two).

[jperedo]

Phil-

Have not looked around John's site recently and while snooping around in a free moment noticed this forum thread and could not resist - based on my data your observations are quite valid and very important.

Supination (an external rotation of the forearm as if one were holding a bowl of "s(o)up" in the palm of their hand) is a natural, and perhaps the most important, attribute of the vertical component of the looped back swing path. In other words, the forearm will be rotated externally to facilitate the downward racquet motion - EVERY looper does this to some extent.

The importance relates to the muscular conditions of the internal forearm rotators which pronate the forearm near the contact point and are the source of the most efficient action to generate the vertical racquet speed component needed for topspin. These internal rotators are contracted to slow the afore mentioned external rotation, prior to actually accomplishing internal rotation (pronation) of the forearm. This slowing contraction is a "pre-tensing" which eliminates the problem of TIME to maximum force production found if starting from a relaxed state. Also, it does activate most, if not all, other beneificial aspects of the "stretch-shorten" cycle if executed correctly.

In short, the supination/pronation chain of events is a counter movement pattern that greatly facilitates action of the forearm internal rotators. We routinely quantify the extent to which this mechanism is used as an indicator of prowess in stroke mechanics at our player development center. It is extremely important on the forehand, backhand, and serve, it is independent of grip style, and having identified this years ago I've always been surprised the tennis gurus had not noticed it earlier - nice work in recognizing its relevance- Brian

Out of curiosity, does a bigger loop increase activation of the internal rotators?

[BrianGordon]

Out of curiosity, does a bigger loop increase activation of the internal rotators?

The efficacy of muscle contraction (here the forearm internal rotators) has been shown to increase based on the speed of eccentric (trying to shorten) lengthening in the SSC assuming the other components are present.

The speed of lengthening is linked to the speed of the racquet in the vertical component of the loop.

The speed of the racquet at this stage could be enhanced by increasing range of motion or increasing the size of the loop - so yes.

As a practical matter, however, huge loops can create other problems so I always try to maximize vertical speed in tighter patterns of motion.

Aside from the obvious benefits of this, I find this method conducive to the critical racquet positioning as the hand starts to pull forward, the force on the racquet from which, is perhaps more critical in tending to cause the external rotation of the forearm as the racquet proceeds into the forward swing.

[mntlblok]

Aside from the obvious benefits of this, I find this method conducive to the critical racquet positioning as the hand starts to pull forward, the force on the racquet from which, is perhaps more critical in tending to cause the external rotation of the forearm as the racquet proceeds into the forward swing.

Google has been of no help (other than with PFER - pathologic forearm external rotation) in defining "external rotation of the forearm" for me. Got a quickie definition handy?

Kevin
Savannah

[jperedo]

Please correct if i'm wrong -

internal rotation = pronation
external rotation = supination

[BrianGordon]

Google has been of no help (other than with PFER - pathologic forearm external rotation) in defining "external rotation of the forearm" for me. Got a quickie definition handy?

Kevin
Savannah

Hey Kevin - how's the game? see jperedo above - that is how I am using the term(s) - the generic terminology - BG

[mntlblok]

Hey Kevin - how's the game? see jperedo above - that is how I am using the term(s) - the generic terminology - BG

Thanks to you and John Y., I'm slowly making progress with the forehand. The hand is taking a flatter path and, thanks to your picking up on my "over-supination" in my loop (to the point of opening the racket face), it's starting to look like there might be some hope. :-) Sure glad I videotaped your lesson in Cincinnati.

What I *have* gotten good at is lucking into good partners for 50's doubles tournaments.

http://tennislink.usta.com/tournaments/TournamentHome/Results.aspx?T=64413&E=7

http://tennislink.usta.com/tournaments/Draws/EventDraw.aspx?T=54260&E=10

http://tennislink.usta.com/tournaments/Draws/EventDraw.aspx?T=54884&E=14

Kevin